The muscular dystrophies are a group of diverse, heritable neuromuscular disorders which represent a group of devastating neuromuscular diseases characterized by primary or secondary skeletal muscle involvement. Duchenne muscular dystrophy (DMD) is an X-chromosome-linked disease and the most common form of muscular dystrophy. DMD affects 1 in 3500 live male births with patients suffering from chronic muscle degeneration and weakness. Clinical symptoms are first detected between the ages of 2 and 5 years and, by the time the patient is in their teens, the ability for independent ambulation is lost. Death typically occurs in the patient before they are 30 years old due to cardiopulmonary failure.
Congenital muscular dystrophy (CMD) refers to a group of heritable neuromuscular disorders characterized by muscle weakness at birth or in infancy. Affected infants will present with poor muscle tone and few movements. The quality of life and life span of the child is affected through progressive muscle wasting, respiratory compromise, and spinal rigidity. Merosin deficient congenital muscular dystrophy (MDC1A) is the most common and severe form of congenital muscular dystrophy, accounting for 30-40% of all CMD diagnosed cases. MDC1A is characterized by congenital hypotonia, distinct joint contractures, and a lack of independent ambulation. Feeding tube placement and positive pressure ventilation is often required for the respiratory problems that occur. MDC1A has no cure and patients often die before they reach the age of ten years. Currently there is no cure for either DMD or MDC1A.